Steam-trap.



LW. BARTON.

STEAM TRAP.

APPLICATION FILED MAR.13,1909.

Patented Nov.v 30, 1909.

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JOI-IN W. BARTON, OF CLEVELAND, OHIO.

STEAM-TRAP.

Specification of Letters Patent.

'Patented Nov. 30, 1909.

Driginal application led November 21, 1908, Serial No. 463,815. Divided and this application filed March 13, 1909. Serial No. 483,175.

To all whom 'it may concern:

Be it known that I, Jol-IN IV. BARTON, a citizen of the vUnited States, residing at Cleveland, in the county of Cuyahoga and State of Chio, have invented certain new and useful Improvements in Steam-Traps, of which the following is a specification.

This application is a division of my pending application, No. 463,815, filed Nov. 21, 1908, and the invention relates to steam traps of the type having an expansion tube.

The present case and the invention covered thereby relates especially to means to produce a result which is not, so far as I know, possible with any other steam trap; that is, a trap constructed according to this invention will operate automatically with either a vacuum or a gravity system of steam heating, and this result follows from the relative coeiiicients of expansion of the tubes used in constructing the trap, and the relative size of the valve opening, as more fully defined and explained hereinafter.

Merely for the purpose of illustration a form of trap is shown in the accompanying drawings to which the invention is applicable, but it may also be applied to expansion tube traps of various other types, and no limitation with respect to the scope of the invention is implied by reason of the particular forni of trap shown and described herein.

In the accompanying drawings, Figure 1 is a longitudinal section of the trap used for the purpose of illustration. Figs. 2, 3 and 4 are sections on the lines 2 2, 3 3 and 1 -A1 of Fig. 1 respectively.

The particular mechanical construction of this trap will be found fully described in the pending application above referred to, and for the purposes of the present case, the following parts are speciied:

A is an expansion tube screwed at one end into the fitting H. This tube is located within and spaced from the outer tube B which is also screwed into the bell of the liitting H. The opposite end of the tube B is screwed into the casing I of the main valve. The end of the expansion tube is provided with a tubular valve seat E which may be screwed on to desired adjustment. Between the tubes A and B is an annular space or vacuum chamber which is closed at one end, but which opens at the other end into the valve casing through spaces around the valve seat E and through holes K in a guide formed in the valve casing. The valve disk D is connected to a screw stem G by which the valve E is opened or closed or adjusted. The inlet to the trap is through the iitting H, and the outlet is at L, which latter will or may be connected to a vacuum pump or to a waste outlet.

In the annular space between the tubes A and B is a tubular casing N which is not material to the present invention and which is fully described and claimed in the said application and which needs no further reference here except to say that it preserves a dead air space around the tube A. It may be omitted without affecting the invention claimed herein. i

In operation the valve disk is properly aoljusted to allow condensation to escape as it forms. Vhen a vacuum pump is used a vacuum is drawn in the annular space between the tubes B and N, or between the tubes B and A if the tube N is omitted, thereby making said space non-conducting, which keeps the outer tube B cooler than the expansion tube A. If the vacuum pump should fail to work, the steam enters the space between theA tubes and expands the outer tube B, thereby opening the valve far enough to allow the escape of the water of condensation. As long as the pump is working the expansion tube A operates in the usual manner to open or close the valve according to the degree of heat. Ports K prevent tiie expansion of the valve seat from closing or cutting ott' the opening to the vacuum chamber, and consequently the trap will work under all conditions.

IVhen the vacuum pump is working the inner tube A expands as usual, but the outer tube B does not relatively expand because of the vacuum therein, and consequently the steam does not reach said tube B, and also, the flow of condensation is not through the same, and the increase of vacuum tends to tix cool the outer tube. When the vacuum pump stops the hot vapor or water will pass through the holes K into the outer tube and. expand the saine, thereby opening the valve and increasing the lift thereof, which latter point is of decided importance. Hence the trap is adapted for use with either a vacuum system or a gravity system, and in either case the expansion tube A operates in the usual manner to open or close the valve according to the degree of heat, which is a result hitherto unknown. This result follows from the relative coefficients of expansion of the inner tube A and the outer tube B, and the relative size of the valve opening. The coetlicient of expansion of the inner tube is considerably greater than that ot the outer tube, for if the outer tube should expand as much as the inner tube, the trap would not operate with a gravity system, because the outer tube would expand practically as much as the inner tube, and thereby force the valve away from the seat, or, in other words, the seat would never overtake the valve, without readjustment of the valve. In my device the ratio of expansion of the inner tube A is so much greater than that of the outer tube B that the Valve seat closes against the valve at the temperature of steam, and the area of the valve is so large that the necessary escape of any condensation will occur without drawing the valve seat a great distance from the valve. The area oIp the valve should be in proportion to the length of the expansion tube, that is, the longer the tube the larger the area of the valve must be, in order to adapt the trap for automatic use with both a vacuum system and a gravity system, a large valve area being required on a long tube to allow a suliiciently rapid escape or l'low to clear the whole tube of condensation in order to effectthe desirable instantaneous or immediate action of the trap.

The trap may be constructed according to a general formula for calculating the proper length of tubes, so that the expansion of the outer tube will be suiiicient to compensate for the fall in pressure diterence available for causing discharge, if the vacuum should be destroyed. Tt is assumed that there is 1 lb. per sq. inch above atmospheric pressure, in the inner tube at all times. It is also assumed that there is a vacuum of 14 (or 7 lbs.) normally when the pump is operating; but that if the pump stops this back pressure rises to atmospheric pressure.

The length of the tubes must be calculated in terms of a certain rate of discharge through the trap. Atany rate greater than this the water will collect in the inner tube; at any less rate there will be no collection of water in the inner tube. Let this rate of discharge W lbs. per hr.

Symbols used: y

Vzrate of discharge, in lbs. per hr.

g: rate of discharge, in cu. ft. per sec.

F I area of valve opening in sq. inches.

7L z available head for causing discharge.

ccoefticient of valve oriiice (assumed .6 l

g CFV 2 32.2 h (from Hydraulics.)

171.223 press. in lbs. per sq. inch. 7L: 2.3 8: 18.4 ft. when pump operates. 77. z: 2.3 1 I 2.3 ft. when pump does not operate] From above formula- F .000081 )N sq. in. when pump operates.

F .000088 )Y sq. in. when pump does not operate.

Zzopening of valve from its seat (in inches.) Z diam. of valve. Hence.-

F Zia W Z- .000010 when pump operates.

00028 g when pump does not operate.

a: .00000599 32 XL This is the final expression for L, the length of tube to discharge lV lbs. per hr. with no water collecting in inner tube. Thus in a sample trap,

lf WV be assumed as 125 lbs. per hr.

L z l z Hence the tube should be made 15.6 long in order to discharge 125 lbs. of water per hr. with none collecting in the inner tube, and hence no contraction of the inner tube.

A general expression of the equation, instead of the concrete and special values above given, may be derived from the following equations:

L Q #9 =oTL C/WdCn/yb n Q/2gh-vac. The final form then is l Q q a CTL @'ClCx/qh V2gh-vac. the coeflicient c being inserted to take care of the discharge from the orifice not being quite equal to the theoretical discharge. The equation could be reduced slightly further and solved for L thus:

lt has been found that a trap constructed according to this invention will work perfectly, without adjustment, on a heating system using vacuum at times and gravity at other times, as on day and night work where the pump is operated during the day and idle during the night, which is not true of any other trap known to me, and a device of great utility is provided for use under variable conditions, without necessity for the constant attention and manipulation re quired with existing traps.

l claim:

1. A steam trap having inner and outer expansible tubes, and a valve carried by the outer' tube and coperating with the inner tube to open or close the same, the coetlicient of expansion of the inner tube being greater than that of the outer tube, and the length and coefficient of expansion of the outer tube being in a proportion to the area of the valve opening proper to allow escape of condensation in the presence of a partial vacuum or otherwise.

2. A steam trap having inner and outer expansible tubes, a valve casing and valve carried by the outer tube, and a valve seat carried by the inner tube, the coefficient of expansion of the inner tube being greater than that of the outer tube, and the length and coetlicient of expansion of the outer tube being in a proportion to the outlet area of the valve seat proper to allow escape of condensation in the presence of a partial vacuum or otherwise.

3. A steam trap having inner and outer expansible tubes, and a valve cooperating with the inner tube and opened or closed by variations in the length thereof, the length and coeflicient of expansion of the outer tube being proper to compensate for the decrease in effective discharge pressure due to the failure of vacuum in the trap discharge by causing a corresponding increase in the discharge area between the valve and the inner tube when the valve is open.

t. A steam trap having inner and outer expansible tubes, and a valve carried by the outer tube and coperating with the inner tube to open or close the latter, the length of the outer tube corresponding to the formula L= 1r (AAL) CTada/2g x/h x/h. vac.

as specified.

5. A steam trap for vacuum heating systems having an outer expansion tube and an inner expansion tube whose coetiicient of expansion is greater than that of the outer tube, the space between said tubes being always in communication with the discharge outlet from the trap, and a valve means connected to said outer tube which acts to control the area of discharge through said inner tube according to its expansion and contraction relative thereto, the length and coeficient of expansion of said outer tube bearing such a relation to the dimensions of the valve mechanism that the amount discharged from the trap will not be affected by cessation of the vacuum in the discharge outlet.

In testimony whereof, I affix my signature in presence of two witnesses.

JOHN W. BARTON.

Vitnesses:

JOI-IN A. BOMMHARDT, MONROE E. MILLER.

l l l' l l It is hereby certified that in Letters Patent No. Qlew, granted November 30, 1909, upon the application of John W. Barton, of Cleveland, Ohio, for an improvement in Steam-Traps, errors appear in the printed specification requiring' correction :is follows: Page 3, line 3h', and line 91, n the equations, the letters I should read l, (unity); and that the said Letters Patent should be reed with these corrections therein that the saine may conform to the record of the ease in the Patent Oflice.

Signed and sealed this 5th day of April, A. D., 19.10.

[SEAL] o. o. BILLINGS,

Acte/'wg Commssz'ower Qf Patents. 

